The invention relates to a method for detecting the activation of brake lights of vehicles driving in front, in which a vehicle driving in front is recorded with an image sensor, and a signal is issued when it is detected that the brake lights light up, which can be converted in a warning device and/or in a vehicle assistance system.
In patent application EP 0380 797, the detection of the tail lights of a motor vehicle is described in the infrared range with a CCD image sensor. The advantage of detection with a CCD image sensor in the infrared range is that the sensitivity of the image sensor is higher than that of the human eye in the visible red spectral range, so that reliable functioning is guaranteed with a wide range of light and weather conditions. With a recorded beam intensity above a specified threshold value, i.e. when the distance between the vehicles has not reached a critical level, a warning signal is triggered. In order to detect the activation of the brake lights, an additional infrared signal which can be modulated is provided on the vehicle driving in front, the modulation of which alters during the braking procedure. When the modulation is altered, a warning signal is also issued. The warning signals are converted in a warning device and/or a vehicle intervention.
In the publication DE 19734005, a device for reducing the brake path of motor vehicles is presented which makes use of an infrared sensor for detecting when a brake light on the vehicle driving in front lights up. In a situation which is estimated to be critical, e.g. when the brake lights are activated and there is a short distance between the vehicles, a warning signal is generated and appropriate measures are initiated, such as warning the driver, activating the brake pedal and pre-loading the brake system.
The object of the invention is to provide a method for also rapidly and cost-effectively detecting the activation of brake lights of vehicles which are driving in front which do not emit an additional or a modulated signal during the braking procedure.